A5103249629- Laser-Plasma Interactions and Diagnostics
- Laser-induced spectroscopy and plasma
- Laser-Matter Interactions and Applications
- Computational Physics and Python Applications
- Atomic and Molecular Physics
- High-pressure geophysics and materials
- Geological and Geophysical Studies
- Magnetic confinement fusion research
- Scientific Computing and Data Management
- Machine Learning in Materials Science
- Model Reduction and Neural Networks
- X-ray Diffraction in Crystallography
- Neural Networks and Applications
- Dust and Plasma Wave Phenomena
- Radiation Therapy and Dosimetry
- Ion-surface interactions and analysis
- Particle Accelerators and Free-Electron Lasers
- COVID-19 epidemiological studies
- Advanced Radiotherapy Techniques
- Advanced Adaptive Filtering Techniques
- Geotechnical and construction materials studies
- Multimedia Learning Systems
- Advances in Oncology and Radiotherapy
- Anomaly Detection Techniques and Applications
- Electron and X-Ray Spectroscopy Techniques
University of Oxford
2015-2024
State University of Gorontalo
2021-2024
State University of Makassar
2023
Politeknik Negeri Banjarmasin
2019-2020
Jakarta State Polytechnic
2019-2020
University College London
2016
Bandung Institute of Technology
2013
Background : Leprosy-related disability is a challenge to public health, and social rehabilitation services in endemic countries. Disability more than mere physical dysfunction, includes activity limitations, stigma, discrimination, participation restrictions. We assessed the extent of its determinants among persons with leprosy-related disabilities after release from multi drug treatment. Methods conducted survey on affected by leprosy Indonesia, using Rapid Appraisal toolkit based...
The Advanced Proton Driven Plasma Wakefield Acceleration Experiment (AWAKE) aims at studying plasma wakefield generation and electron acceleration driven by proton bunches. It is a proof-of-principle R&D experiment CERN the world׳s first experiment. AWAKE will be installed in former CNGS facility uses 400 GeV/c beam bunches from SPS. experiments focus on self-modulation instability of long (rms ~12 cm) bunch plasma. These are planned for end 2016. Later, 2017/2018, low energy (~15 MeV)...
Computer simulations are invaluable tools for scientific discovery. However, accurate often slow to execute, which limits their applicability extensive parameter exploration, large-scale data analysis, and uncertainty quantification. A promising route accelerate by building fast emulators with machine learning requires large training datasets, can be prohibitively expensive obtain simulations. Here we present a method based on neural architecture search build even limited number of data. The...
Improving the predictive capability of molecular properties in ab initio simulations is essential for advanced material discovery. Despite recent progress making use machine learning, utilizing deep neural networks to improve quantum chemistry modelling remains severely limited by scarcity and heterogeneity appropriate experimental data. Here we show how training a network replace exchange-correlation functional within fully-differentiable three-dimensional Kohn-Sham density theory (DFT)...
Automatic differentiation represents a paradigm shift in scientific programming, where evaluating both functions and their derivatives is required for most applications. By removing the need to explicitly derive expressions gradients, development times can be shortened calculations simplified. For these reasons, automatic has fueled rapid growth of variety sophisticated machine learning techniques over past decade, but now also increasingly showing its value support ab initio simulations...
Abstract This paper presents a study of early epidemiological assessment COVID-19 transmission dynamics in Indonesia. The aim is to quantify heterogeneity the numbers secondary infections. To this end, we estimate basic reproduction number $$\mathscr {R}_0$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mi>R</mml:mi><mml:mn>0</mml:mn></mml:msub></mml:math> and overdispersion parameter {K}$$ xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>K</mml:mi></mml:math>...
AWAKE is a proton-driven plasma wakefield acceleration experiment. % We show that the experimental setup briefly described here ready for systematic study of seeded self-modulation 400\,GeV proton bunch in 10\,m-long rubidium with density adjustable from 1 to 10$\times10^{14}$\,cm$^{-3}$. short laser pulse used ionization vapor propagates all way along column, suggesting full vapor. occurs bunch, at time and follows affects bunch.
Abstract The advent of x-ray free-electron lasers has enabled a range new experimental investigations into the properties matter driven to extreme conditions via intense x-ray-matter interactions. femtosecond timescales these interactions lead creation transient high-energy-density plasmas, where both electrons and ions may be far from local thermodynamic equilibrium. Predictive modelling such systems remains challenging because different at which thermalize, vast number atomic...
Our understanding of physical systems generally depends on our ability to match complex computational modelling with measured experimental outcomes. However, simulations large parameter spaces suffer from inverse problem instabilities, where similar simulated outputs can map back very different sets input parameters. While fundamental importance, such instabilities are seldom resolved due the intractably number required comprehensively explore space. Here we show how Bayesian machine...
Shadowgraphy is a technique widely used to diagnose objects or systems in various fields physics and engineering. In shadowgraphy, an optical beam deflected by the object then intensity modulation captured on screen placed some distance away. However, retrieving quantitative information from shadowgrams themselves challenging task because of nonlinear nature process. Here, we present method retrieve shadowgrams, based computational geometry. This process can also be applied proton...
The design of inertial confinement fusion (ICF) ignition targets requires radiation-hydrodynamics simulations with accurate models the fundamental material properties (i.e., equation state, opacity, and conductivity). Validation these are required via experimentation. A feasibility study using spatially-integrated, spectrally-resolved, X-ray Thomson scattering (XRTS) measurements to diagnose temperature, density, ionization compressed DT shell hot spot a laser direct-drive implosion at...
A prevalent class of challenges in modern physics are inverse problems, where physical quantities must be extracted from experimental measurements. End-to-end machine learning approaches to problems typically require constructing sophisticated estimators achieve the desired accuracy, largely because they need learn complex underlying model. Here, we discuss an alternative paradigm: by making model auto-differentiable can construct a neural surrogate represent unknown quantity sought, while...
The free-free opacity in plasmas is fundamental to our understanding of energy transport stellar interiors and for inertial confinement fusion research. However, theoretical predictions the challenging dense plasma regime are conflicting there a dearth accurate experimental data allow direct model validation. Here we present time-resolved transmission measurements solid-density Al heated by an XUV free-electron laser. We use novel functional optimization approach extract...
The development of high-brightness free-electron lasers (FEL) has revolutionised our ability to create and study matter in the high-energy-density (HED) regime. Current diagnostic techniques have been very successful yielding information on fundamental thermodynamic plasma properties, but provide only limited or indirect detailed quantum structure these systems, how it is affected by ionization dynamics. Here we show electronic solid-density nickel, heated temperatures 10's eV femtosecond...
We present experimental observations of K_{β} emission from highly charged Mg ions at solid density, driven by intense x rays a free electron laser. The presence indicates the n=3 atomic shell is relocalized for high charge states, providing an upper constraint on depression ionization potential. explore process state relocalization in dense plasmas first principles using finite-temperature density functional theory alongside wave-function localization metric, and find excellent agreement...
Abstract State of the art X-ray Free Electron Laser facilities currently provide brightest pulses available, typically with mJ energy and several hundred femtosecond duration. Here we present one- two-dimensional Particle-in-Cell simulations, utilising process stimulated Raman amplification, showing that these are compressed to a temporally coherent, sub-femtosecond pulse at 8% efficiency. Pulses this type may pave way for routine time resolution electrons in nm size potentials. Furthermore,...
A new physical model of the hosing instability that includes relativistic laser pulses and moderate densities is presented derives density dependence equation. This tested against two-dimensional particle-in-cell simulations. These simulations further examine feasibility using multiple to mitigate in a Nd:glass-type parameter space. An examination effects planar versus cylindrical exponential gradients on also presented. The results show strongly more geometries are capable mitigating which...
Proton radiography is a technique in high-energy density science to diagnose magnetic and/or electric fields plasma by firing proton beam and detecting its modulated intensity profile on screen. Current approaches retrieve the integrated field from require unmodulated before interaction, which rarely available experimentally due shot-to-shot variability. In this paper, we present statistical method without needing know exact source profile. We apply our experimental data, showing robustness...
This is a pedagogical paper on estimating the number of people that can be infected by one infectious person during an epidemic outbreak, known as reproduction number. Knowing crucial for developing policy responses. There are generally two types such number, i.e., basic and effective (or instantaneous). While average expected cases directly generated case in population where all individuals susceptible, current state population. In this paper, we exploit deterministic...
Proton radiography is a technique extensively used to resolve magnetic field structures in high energy density plasmas, revealing whole variety of interesting phenomena such as reconnection and collisionless shocks found astrophysical systems. Existing methods analyzing proton radiographs give mostly qualitative results or specific quantitative parameters strength, recent work showed that the line-integrated transverse can be reconstructed regimes where many simplifying assumptions were...
Plasma amplifiers offer a route to side-step limitations on chirped pulse amplification and generate laser pulses at the power frontier. They compress long by transferring energy shorter via Raman or Brillouin instabilities. We present an extensive kinetic numerical study of three-dimensional parameter space for case. Further particle-in-cell simulations find optimal seed parameters experimentally relevant constraints. The high-efficiency self-similar behavior is observed only seeds than...